America's laws about sex offenders are full of well-intentioned confusion

WHILE flying from Bangkok to Los Angeles earlier this week, John Mark Karr ate a meal of paté, salad, fried king prawns, steamed rice, broccoli and chocolate cake. He drank a beer, then crushed the empty can with his hands. Americans know a lot about Mr Karr's meals—as well as his two marriages, his phone calls to a clinic that performs sex-change operations and his reaction to the impromptu singing of a Bee Gees song—because he has been implicated in one of the country's most notorious crimes.

In 1996 the body of a six-year-old girl, JonBenet Ramsey, was found in the basement of her home in Colorado. She had been struck in the head, garrotted and, perhaps, sexually assaulted. A ransom note demanding the oddly precise sum of $118,000 was also discovered. The police and the media have devoted countless hours to the case; but, until last week, nobody had been arrested.

Ten years ago, the tone of media coverage implied that JonBenet's parents had got away with murder. Mr Karr's arrest in Thailand led to some sharp changes in direction. “Solved”, announced the New York Daily News on August 17th. Television reporters helpfully pointed out that Thailand is known for sex crimes, and that Mr Karr slightly resembles Tony Perkins, the star of “Psycho”. From internet sleuths came the news that the suspect had tried to set up a website for children.

A few days later, the case seemed less clear-cut. Although Mr Karr had told reporters he was with JonBenet when she died, his family questioned that. It transpired that he had a deep interest in child killings and an active fantasy life. After these revelations, the tone of media coverage changed again, although only slightly. The current consensus is that Mr Karr is either a killer or a delusional paedophile, and ought to be locked up in either case.

It is not surprising that suspicion should adhere so readily to someone like Mr Karr. Americans fear nothing more than the stranger who targets children. A Gallup poll last year found that 66% of respondents were “very concerned” about child molesters. Only 52% of people worried as much about violent crime, and just 36% fretted about terrorism.

Such fears have driven changes to the law. At the time of JonBenet's murder, three states had restricted where convicted child molesters and other sex offenders could live. By 2004 another 11 had done so, according to David Singleton of the Ohio Justice and Policy Centre. Similar laws are being considered by another 12 states and by a rapidly growing number of towns. A typical law, approved this week by Monroe, New Jersey, prevents some sex offenders from living within 2,500 feet (762 metres) of any school, child-care centre, playground, library or place of worship —in other words, just about anywhere.

The evidence that such laws protect children is thin. Most children are harmed by family members or acquaintances. The last time the Justice Department looked in detail at the matter, in the late 1990s, it found that just 3% of child molesters were re-arrested for a similar crime within three years of being released from prison. Seven “ordinary” ex-convicts—robbers, burglars and the like—were arrested for molesting children for every one convicted child sex offender who was collared for the same offence. So much for history being destiny.